Manufacture of sound films



Juiy 17, 1934., sag-10 1,966,873

MANUFACTURE OF SOUND FILMS Filed Nov. 21, 1932 3 Sheets-Sheet 1 in vanfor @JMG I July 17, 1934:. F soc b 1,966,873

MANUFACTURE OF SOUND FILMS Filed Nov. 21. 1932 :5 Sheets-Sheet 2lnveni'or: By Affam 2 July 17 1934. F. SOCHOR MANUFACTURE OF SOUND FILMSFiled Nov. 21, 1932 3 Sheets-Sheet 3 In ven for 8 Ah I y orney i1,966,873 PATENT OFFICE MANUFACTURE OF SOUND FILMS Franz Sochor, Vienna,Austria, assignmto A:

Ansco Corporation, B

inghamton, N. Y., a cor- I poration of New York Application November 21, 1932, Serial No. 643,706

In Austria March 19, 1931 5 Claims.

For the mechanical recording of sound records on narrow films or othersupports of a material harder than wax, a number of processes is known.According to these processes the groove is either cut out in thematerial (cutting method) or impressed therein (impressing method). Thislatter process may be carried out with a cold stylus as well as with aheated one. In principle, this latter process consists in a displacementof the material so that the places adjacent the sound line obtain agreater density than those of the remainder of the material, Recordingsounds in a cold way by means of a stylus, irrespective of whether it iscarried through according to the cutting method or according to theimpressing method, is associated with the essential drawback hithertoinevitable that the record line at its upper edges, i. e. at the placewhere it adjoins the surface of the film-band receives a more or lessstrong bur which gives rise to intense extraneous noises during thereproduction of the film. These extraneous noises may be so strong thatit is quite impossible to arrive at a faultless reproduction of thesound. The application of the said known processes is particularlyimpossible in the case of narrow films which have been producedaccording to the reversal method.

The process according to this invention consists in producing a soundgroove in such a manner that the material of the film displaced bydepression of the groove stands out in form of a boss on the inversedside of the film without any molecular displacement being produced. Dueto the solidity of the material employed and to its special propertieswhich make it useful for the very purpose in question, the sound grooveas well as the boss are preserved. The marginal regions of the soundgroove produced are likewise employed for the record of sound. Theparticular advantage involved in the new process, lies in the fact thatany formation of a bur at the upper edges of the groove is renderedimpossible. Thus the walls of the record groove pass softly into theplane part of the support. Another advantage provided by the new processresides in the fact that the recording needles used need no longer havesharp edges, but can be provided with an active surface of anaccordingly narrow and rounded form. This kind of needle will hereafterbe described more fully.

In order to enable reproduction to be satisfactorily obtained from agroove in which the material stands out on the reverse side of the base,the dimensions of the groove are important when the record is to bereproduced with the aid of a stylus.

This invention comprises a method of mechanically recording sounds on arecord base of preferably a band-like form, for instance on acinematographic film for amateur purposes by depressing on the margin ofthe base a groove in such manher that the material displaced stands outon the reverse side of the base in the form of a boss without moleculardisplacement, the dimensions of the impressed groove being such that theratio of its depth to its breadth at the upper edges is between 1:1 and1:2.

In order to avoid that during the recording and reproduction of soundsthe film band not having the necessary degree of rigidity, and being inparticular comparatively soft in comparison with the steel of the stylusis not displaced from its true path by the latter, thus giving rise toimpure and confused tones, the film is guided at the place of record,for a considerable length between a roller and a tightening cap exactlyfitting thereon. In a preferred form of construction according to thisinvention the guide of the film extends over about half the roller. Thusthe film band, as already stated, is given an additional stiffness, sothat the marginal portions of the sound groove can no longer give way tothe reproducing stylus. On the other hand the film is prevented frombending too much, as it is the case in the reproducing devices fittedwith grooved supports, for instance grooved rollers.

By the device according to this invention it is furthermore realizedthat the sound groove, owing to the film being bent, is somewhatenlarged so that the stylus can scan the track conveniently.

For the known processes of recording sounds, above referred to, use hasalready been made of styli having prism-shaped heads in the form ofpyramids with three or four edges. The an terior and, if necessary, theposterior cutting edge of these pyramids form an angle with the plane ofthe record base which may raise to 45. Moreover, these pyramid-shapedheads are pro- .vided with lateral imprinting edges of a distinctstraight form, being inclined to one another to form an angle of between90 and 135.

As it is important that the structure of the film is not injured whilethe groove is produced,

the stylus employed according to the invention is cone-shaped and isground to produce one facet or two facets such that the stylus does notproduce a sharp edge at the bottom of the sound groove which would giverise to fissures and cracks in the band-shaped sound base.

The process which is the object of this invention will be more fullyexplainedwith reference to the accompanying drawings which represent, byway of example, one form of construction of the device, of the recordingstylus and of the reproducing stylus with which said process is carriedout.

Fig. 1 shows diagrammatically a side view of an arrangement forrecording sounds according to the present invention, part being shown insection.

Fig. 2 is a front elevation of the arrangement according to P18. 1.

Fig. 3 is a diagrammatic representation of the device for guiding thefilm provided with the tightening cap.

Pig. 4 is a side view of the device according to Fi 3.

Fig.5isaplanviewofthedevice accordingto Fig. 3.

Fig.8isasectionontheline88of1"ig.5.

Fig.7isasectionontheline77ofl"lg.5ofa particular form of constructionwhich, however, is given only by way of example.

Fig. 8 is a side view of the recording stylus.

Fig. 8 is a front view thereof.

Figs. 10 to 12 show a modified form of the recording stylus according tothis invention.

Figs. 13 and 14 show other two modified forms of the recording stylus.

Fig. 151s a cross section through an arrangement of the bandshapedrecord base (film), its support and the recording stylus, drawn on aconsiderably enlarged scale.

Fig. 18 shows, equally on an enlarged scale, the end of the reproducingstylus.

Fig. 17 is a section through the record base and several forms of thereproducing stylus, all being represented on an enlarged scale.

Fig. 18 represents two views of the recording stylus.

Fig. 19 represents two views of the reproducing stylus.

In carrying out the process according to this invention the film travelsover the usual propelling members (feed drums) driven in known manner soas to ensure a continuous feed of the film at the place where the soundis to be recorded, the fllm 1 being supported by a roller 2 of suitablesize. The roller is provided with a groove 3. The depth and width ofsaid groove must be such that the grooved part of the film material doesnot come into touch with the edges of the said groove 3. It is essentialto give the pressed groove such a form that the proportion of its depthto its breadth is 1:1 to 1:2.

The film-band is guided preferably over half the circumference of theroller and pressed to said roller by means of a cap-like member 3ahaving a notch 7, so that the film receives an additional stiffness andthe reproducing needle 4, during the reproduction of the sound, caneasily scan the sound line, without the wall portions of the groovegivingvway to the needle any longer.

In the form of construction represented in Figs.

- 3-7 1 is the film-band provided or to be provided with the recordgroove and 2 is the drum or cylinder. 6 is the cap for tightening thefilm having an opening 7. 8 is a stationary flange mounted to the baseplate 20. The cap 8 is provided with two lateral ridges 9 and 10, ofwhich ridge 10 extends not only upwardsas does' likewise ridge 9, butalso grips over the edge of the film roll 2. The ridges 9 and 10 formthe bearing for an axle 11 having a lever 12 which, as represented inFigs. 5 and 8 is fastened to a casing 14, to which is mounted, forinstance, by soldering, another lever 15, which by means of a screw 18is connected to the wall 10. The casing 14 comprises a widened portion14a and a portion 14b milled on its outer surface. Arranged between thefrontal extension of the part 144 and the front of the extension 17 ofthe axle 18 which serves to carry the casing 14, is a spring 19 by. theaction of which the casing is permanently pressed towards the wall 20,into which the axle 18 is mounted. The casing 14 provides notches 21 and21a, which in various positions may engage with a pin 22 which is fixedto the axle 18. The notches 21, 21:: are preferably chosen somewhatlarger than the diameter of the pin 22. By this arrangement the cap canbe kept in one of two positions, having some play in each position. Aspring 23 fixed to the casing 14 at 24 and to the wall 20 at 25 tends topress the cap 8 against the roller 2 supporting the film.

As can be seen from Figs. 5, 6 and 7 neither the roller 2 nor the cap 9is pressed against the stationary flange 8. The space left between therevolving roller 2 and the flange 8 is preferably very small. The loweredge of the flange 10 extending over the roller 2 is not in contact withsaid roller 2 but with the left edge of the film stripe 1 (Fig. 7). Theright edge of the film stripe makes contact with the stationary flange8. The cap 6, in consequence, is pressed against the film l by thesprings 19 and 23 in the direction of the arrows a: or 11 (Fig. 7),whereby the film is pressed against the flange 8 and the roller 2respectively thus being securely guided.

In the device according to this invention insertion and removal of thefilm is very easy. After drawing the casing 14 with the members mountedthereon including the curved guide member 8, in the direction oppositethe strain of the spring 19, i. e. in the direction indicated by thearrow p (Fig. 5), it can be turned in oppo-- sition to the strain of thespring 23, as indicated by the arrow Pl (Fig. 4). To introduce the film,the casing together with the members is mounted 1 thereon, as described,is moved in the direction described and kept in its tilted position bymeans of the pivot 22 which engages with the notch 210. After havingintroduced the film, the casing is moved in the inversed sense so that,when the cap 8 embraces the film, the spring 23 transmits the pressureover the lever 12 to the said cap 6, while the spring 19 presses the cap8 against the film in a horizontal direction.

It is of course to be understood, that modifications within the scope ofthe invention are possible. If, for instance, the cap 6 together withits lateral walls moves in special guide-rails which do not allow thismember to be shifted sidewards, the lever 15 as well as the spring 19 0and the downwards extension of the wall 10 can be dispensed with. Inthis case the film is only pressed against the roller 2; this may be asumcient guide for the film.

The roller 2, may, ofcourse, also be provided 13'.- with toothed edgesand then serve as transporting roller (with driving means). In this casethe cap 6 is provided with two grooves or slots of large dimensions, sothat the cap may be moved in an axial direction to the roller withoutthe teeth being injured.

The recording needle which serves for the production of the groove inthe recording base and must accordingly be leaded with a suitableweight, chiefly consists of a cylinder 4 and a cone 5.

According to Figs. 8 to 12 the cutting edges of the cone with which thegroove is produced are inclined to one another so as to form an angle aof between 47 and 57 (on an average 52). 145 Near its point this cone isground in view of the production of a. narrow recording line, the facetsobtained being inclined to form an angle 3 of between 117 and 127 (on anaverage 122). Thereby a body is obtained which comprises two 150 levelfacets 6a and 7a and a curved conic surface which does not face the lineof record.

As the outlines of the ground facets 6a and 7a represent conic sections,the edge serving for the production of the sound record in the groove iscurved. Since the curvature extends opposite the direction of movementof the record base, no formation of a bur at the edge of the soundgroove is possible. To obtain a favorable result, the lower edge 8a ofthe grooving means may, with the axis of the recording stylus, form anangle '7 of between 69 and 79 (on an average 74), which, however, can bevaried within small limits.

According to Figs. 10 to 12, representing a special form of therecording stylus, the cone 5 and the cylinder 4 are in an inclinedposition to each other, so that the axis of the cone and that of thecylinder form an angle 6 of between 30 and 40 (on an average 35). Smalldeviations of these values are, however, admissible.

As shown in Fig. 13 the rounded grooving facet provided on the recordingstylus at the conic part 5 between the points 10a and 110 may be anycurved line in the side view, the facets 6a and 7a forming the angle 5above mentioned.

The writing head of the recording stylus, however, may also be given theform represented in Fig. 14. The ground facets 12a, feebly inclined toone another, together with a back plane 14a form the grooving edges 15a,with which the sound records are produced in the impressed groove. Inthis form of construction the narrow-shaped active grooving facet isindicated by 16a.

In another form of construction represented in Fig. 18 the stylus forthe production of the sound records consists, for instance, of acylindrical part 4 and a cone 5 with an angle at thepoint of about 90(between and 100). As represented in Fig. 18 the cone is provided,somewhat above its point, with a ground facet, the inclination 'y ofwhich with the axis of the stylus is about 22 to 32, most advantageously27. As the ground facet does not begin at the point of the cone, butsomewhat above, a better rounding of the recording member is arrived at,so that the record base, too, is rounded at the bottom at 6b. Therecording edges of the recording member are marked 7b (Fig. 15). Duringthe grooving as well as during the recording operation the film,- withinthe reach of the groove provided in the roller, is supported only at theedges 81:, 8b thus hanging free in the groove 3 of the roller 2.

A film which has thus been provided with a sound record, for instance, acinematographic film for amateur purposes, may be reproduced immediatelyafter the record has been picked up to which end a special reproducingstylus is used. This reproducing stylus consists, for instance, of acylindrical portion 10b with a lower extension 11b, the end of which isprovided with a rounding 12?), the axis of which is. as represented inFig. 19, inclined towards that of the stylus. The frontal surface of theportion 11b is provided with a ground facet 13b which is inclinedtowards the axis of the stylus by about 22 to 32, most advantageously by27. In varying the breadth 15b of the portion 11, the sound groove ofthe film band 1 may be followed up by the reproduction stylus indfferent planes a, b, 0, so that, by exchanging the stylus, sound may bereproduced, as represented in Fig. 17, at a, b, c alternately. Therounding of the portion 11b must in any case have a greater radius thanthat of the recording stylus between the edges 1b. By this means thereproducing stylus, while running in the record line, does not reachdown to the bottom of the groove of the record base 1. Scanning of thesound record groove of the record base 1 is only eifected at the points41-1, or e-h, or f-g and 0, never at the whole lines df and g-i at thesame time. Thereby life of the sound record is considerably enhanced.

What I claim is:

1. A device for recording sounds, on a record base of preferablyband-like form, for instance, on a film for amateur purposes whichcomprises means for supporting said base, said means being provided witha groove, a record base on said supporting means, means for pressingsaid record base to said supporting means, and engaging with said baseon a substantial distance, said means being provided with an opening,and recording means including a stylus for depressing on said base agroove engaging with said base through said opening.

2. A device for recording sounds on a record base or preferably bandlike form, for instance, on a film for amateur purposes which comprisesa roller for supporting said base, said roller being provided with agroove, a record base on said roller, means for pressing said recordbase to said roller. and engaging with said base on a substantialdistance, said means being provided with an opening, and recording meansincluding a stylus for depressing on said base a groove engaging withsaid base through said opening.

3. A device for recording sounds on a record base of preferablyband-like form, for instance, on a film for amateur purposes whichcomprises a roller for supporting said base, said roller being providedwitha groove, a record base on said roller, a cap provided with a cutout fitting over said record base on saidroller, means for pressing saidcap on said record base, thus pressing the base against the roller, andrecording means including a stylus for depressing on said base a grooveand engaging with said base through said out out.

4. A device for recording sounds on a record base of preferablyband-like form, for instance, on a film for amateur purposes whichcomprises a roller for supporting said base, said roller being providedwith a groove, a record base on said roller, a cap provided with a cutout fitting over said record base on said roller, a spring actuatedlever system for pressing said cap on said record base, thus pressingthe base against said roller, and recording means including a stylus fordepressing on said base a groove and engaging with said base throughsaid out out.

5. A device for recording sounds on a record base of preferablyband-like form, for instance, on a film for amateur purposes whichcomprises a roller for supporting said base, said roller being providedwith a groove, a record base on said roller, a cap provided with a cutout fitting over said record base on said roller, an axle fixedlymounted, a casing rotatably mounted on said axle, two levers fixedlymounted on said casing and jointedly connected to said cap, a firstspring tending to shift said casing in the direction of axle, a secondspring pressing said cap to on said record base. thus pressing the baseagainst said roller, and recording means including a stylus fordepressing on said base a groove and engaging with said base throughsaid out out.

FRANZ SOCHOR.

